1. Field of the Invention
The present invention relates to an antenna device which is mounted on a radio transmission-reception apparatus such as a base unit and a handset unit of a cordless telephone.
2. Prior Art
In a conventional antenna device for a radio transmission-reception apparatus, a base portion of an antenna element is bent, the leading end or tip portion of the base portion so bent is inserted into a hole formed through a printed-circuit board in the transmission-reception apparatus, and the leading end of the base portion is soldered to a back surface of the printed-circuit board to electrically and mechanically connected to the printed-circuit board.
With the above-mentioned conventional antenna device, however, there is a disadvantage that when vibration and/or impact are applied to the antenna, stress caused by the vibration of the antenna is then applied to the solder-fixed portion of the printed-circuit board to thereby damage the portion, with the result that damage to the electrical and/or mechanical connections between the antenna and the printed-circuit board may occur.
In order to protect the solder-fixed portion against such damage, there has been proposed an antenna device in which a lower portion of an antenna element is wound in a coil so that some of the vibration of the antenna is absorbed by the coiled portion. Even in such a conventional example as this type, however, the solder-fixed portion is still subject to the stress, and thus there is a risk of the solder-fixed portion being damaged by such stress. Furthermore, there is a problem that electrical characteristics of the antenna are affected when the coiled portion is deformed by the stress.
An object of the present invention is to provide an antenna device which can solve the above-mentioned problems inherent in the conventional examples, whereby even when vibrations and/or impacts are applied to an antenna element, the antenna element is prevented from being deformed and electrical and mechanical connection between the antenna element and a printed-circuit board is prevented from being broken.
Another object of the present invention is to provide an antenna device capable of being mounted on a radio transmission-reception apparatus by means of a simple assembling operation, thereby reducing production cost thereof.